Using WB powder and WC-Co powder as raw materials, the cemented carbides with different volume fraction of WB additives were prepared by hot isostatic pressing (HIP) method. Then, the phase constitution, microstructure and mechanical properties of the prepared cemented carbides have been studied. The results show that the super hard WCoB phase is formed by the reaction of WB and Co. With the decrease of Co phase, less WC grains were seperated.. With the increase of the WB addition, the prepared cemented carbides have a lower frictionScoefficients and a better wear resistance and hardness. When the WB addition is 30wt%, the hardness of 1900kg/mm₂ can beattained. The abrasion loss of the sample is 1/10 of that of the WC-Co cemented carbide. However, the fracture toughness of the cemented carbide with WB addition is about 83%-91% of that of the conventional WC-Co cemented carbides.